Breaking and rejoining of disulfide bonds in external glycoproteins of influenza virus.

The treatment of influenza virus with increasing concentrations of mercaptoethanol led to a progressive inhibition of hemagglutinating activity and infectivity and to gradual changes of electrophoretic behavior of virus glycoproteins under nonreducing conditions. These phenomena are most likely the result of consecutive destruction of disulfide bonds in the proteins. So, different disulfide bonds in glycoproteins of native viral particles differ in their sensitivity to the reductant. It has been found that broken disulfide bonds may re-form and the restoration seems to be most rapid in those disulfide bonds that are the least sensitive to the reductant under the native condition.